1. Field of the Invention
The present invention relates to high-frequency modules that perform switching to transmit and receive a plurality of communication signals with different frequency bands.
2. Description of the Related Art
Currently, mobile wireless terminals have a variety of specifications and need to transmit and receive a plurality of communication signals that use different frequency bands. In the case where a utilized frequency band is wide, a mobile wireless terminal is provided with a first antenna that transmits and receives a communication signal that uses a low-frequency band (for example, a band in the vicinity of 900 MHz) and a second antenna that transmits and receives a communication signal that uses a high-frequency band (for example, a band in the vicinity of 2.0 GHz).
A high-frequency module is described in Japanese Unexamined Patent Application Publication No. 2010-212962 that includes a first switch element having a common terminal that is connected to a first antenna and a second switch element having a common terminal connected to a second antenna.
FIGS. 7A and 7B are block diagrams illustrating the configuration of a high-frequency module 10P of the related art having the same configuration as the high-frequency module of Japanese Unexamined Patent Application Publication No. 2010-212962, where FIG. 7A illustrates a case in which either of a transmission circuit and a reception circuit is connected to a first antenna ANT1 and FIG. 7B illustrates a case in which either of a transmission circuit and a reception circuit is connected to the second antenna ANT2.
The high-frequency module 10P includes a switch module into which a first switch element 21 and a second switch element 22 are integrated. A common terminal Pc1 of the first switch element 21 is connected to a first antenna connection terminal 101 of the high-frequency module 10P. A first individual terminal Pi11 of the first switch element 21 is connected to a transmission signal input terminal 111 of the high-frequency module 10P via a low pass filter 31. A second individual terminal Pi12 of the first switch element 21 is connected to reception signal output terminals 1121 of the high-frequency module 10P via a SAW filter 411. A third individual terminal Pi13 of the first switch element 21 is connected to reception signal output terminals 1122 of the high-frequency module 10P via a SAW filter 412. A fourth individual terminal Pi14 of the first switch element 21 is connected to a terminating terminal 113. The terminating terminal 113 is grounded via an external terminating resistor Rt1.
A common terminal Pc2 of the second switch element 22 is connected to a second antenna connection terminal 102 of the high-frequency module 10P. A first individual terminal Pi21 of the second switch element 22 is connected to a transmission signal input terminal 121 of the high-frequency module 10P via a low pass filter 32. A second individual terminal Pi22 of the second switch element 22 is connected to reception signal output terminals 1221 of the high-frequency module 10P via a SAW filter 421. A third individual terminal Pi23 of the second switch element 22 is connected to reception signal output terminals 1222 of the high-frequency module 10P via a SAW filter 422. A fourth individual terminal Pi24 of the second switch element 22 is connected to a terminating terminal 123. The terminating terminal 123 is grounded via an external terminating resistor Rt2.
In the case where transmission or reception is performed with the first antenna ANT1, the common terminal Pc1 of the first switch element 21 is connected to any of the individual terminals Pi11, Pi12 and Pi13, and the common terminal Pc2 of the second switch element 22 is connected to the individual terminal Pi24, which terminates the common terminal Pc2. Furthermore, in the case where transmission or reception is performed with the second antenna ANT2, the common terminal Pc2 of the second switch element 22 is connected to any of the individual terminals Pi21, Pi22 and Pi23, and the common terminal Pc1 of the first switch element 21 is connected to the individual terminal Pi14, which terminates the common terminal Pc1.
Thus, a necessary amount of isolation is secured for transmission and reception circuits respectively connected to the first and second antennas.
However, in a mobile wireless terminal equipped with the high-frequency module 10P of the related art, the terminating resistors Rt1 and Rt2 have to be specially used and along with an increase in the number of constituent elements there is a corresponding increase in size. In addition, regarding the high-frequency module 10P, the terminating terminals 113 and 123 for allowing connection of the terminating resistors Rt1 and Rt2 need to be formed and therefore the size of the high-frequency module 10P is increased by a corresponding amount.
In addition, if an attempt is made to provide the terminating resistors Rt1 and Rt2 inside the high-frequency module 10P, along with there being a need for an area in which to mount the terminating resistors Rt1 and Rt2, there is also a need for routing electrodes therefor, and in this case as well the number of constituent elements and the size of the high-frequency module 10P are increased.